JP2004207006A - Fuel battery cell and fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery cell and a fuel battery in which gas can be uniformly supplied to a plurality of the fuel battery cells with a simple structure. <P>SOLUTION: The fuel battery cell is provided with a columnar cell main body A having a generation part in which gas path 1 with one side as a supply port and the other side as an exhaust port is formed in an axial length direction and a solid electrolyte 7 is pinched by a fuel electrode 5 and an air electrode 9, and a lid-like member 13 which is fitted at the end on the exhaust port side of the cell main body A and is formed with a gas exhaust restraining hole 11 for restraining gas circulation volume of the gas path 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell and a fuel cell, and more particularly to a fuel cell and a fuel cell capable of uniformly distributing and supplying gas to a plurality of cell bodies.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as a next-generation energy, various fuel cells in which a stack of fuel cells is housed in a housing container have been proposed.
[0003]
A fuel cell is constructed by sandwiching a solid electrolyte between an air electrode and a fuel electrode, supplying an oxygen-containing gas to the air electrode, and supplying a gas containing hydrogen or a gas that can be converted to hydrogen to the fuel electrode. As a result, a potential difference is generated between the two electrodes facing each other with the solid electrolyte interposed therebetween, and power is generated.
[0004]
Various combinations of these fuel cells can be considered depending on the electrolyte and form used, but in most cases, the fuel cells generate power by supplying a gas containing oxygen-containing gas and hydrogen, or a gas that can be converted to hydrogen. The points are common.
[0005]
Further, since the fuel cell has a small amount of power generation per fuel cell, the fuel cell is configured by electrically connecting a plurality of fuel cells.
[0006]
Therefore, upon power generation, it is necessary to supply a gas containing oxygen-containing gas and hydrogen, or a gas that can be changed to hydrogen, to each of the plurality of fuel cells. At the same time, the amount of gas supplied to each fuel cell must be the same in order to improve the amount of power generation and power generation efficiency.
[0007]
FIG. 7 shows a longitudinal section of a conventional fuel cell. A porous fuel electrode 5 and a dense solid electrolyte are provided on the surface of a cylindrical columnar porous support 3 having a gas flow path 1 therein. 7. Porous air electrodes 9 are sequentially stacked. When a fuel flows through the gas flow path 1 of the fuel cell and an oxygen-containing gas flows outside the fuel cell, a potential difference is generated between the fuel electrode 5 and the air electrode 9 via the solid electrolyte 7 to generate power. Is A fuel cell is configured by storing a plurality of such fuel cells in a storage container (for example, see Patent Document 1).
[0008]
[Patent Document 1]
JP 10-125346 A
[Problems to be solved by the invention]
In such a fuel cell, it is necessary to supply gas to a plurality of fuel cells at the same time, and in order to stabilize the amount of power generation and power generation efficiency, the amount of gas supplied to each fuel cell is made the same, It is necessary to make the cell fuel utilization uniform. If the amount of gas supplied to each fuel cell is not uniform, the amount of power generated by each fuel cell varies, so that there is a problem that the total amount of generated power is reduced. In addition, there is a problem that a fuel cell in which proper gas supply is not performed is broken.
[0010]
For example, in the case of an anode-supported fuel cell, if the amount of hydrogen-containing gas supplied to the fuel cell is smaller than the design gas amount, the fuel utilization rate increases. If the fuel utilization rate becomes too large, hydrogen, which is the fuel of the fuel cell reaction, is consumed at the gas supply port side of the fuel cell, and no hydrogen is supplied to the gas discharge port side of the fuel cell. A phenomenon occurs.
[0011]
When this phenomenon occurs, the reduced fuel electrode is oxidized, and the portion of the fuel electrode to which hydrogen is not supplied becomes an insulator. When the fuel electrode becomes an insulator, the electric resistance of the fuel cell greatly increases, the electric resistance of the stack in which the fuel cells are configured in series increases, the output greatly decreases, and the fuel cell as a whole increases. The characteristics deteriorate.
[0012]
Conversely, when the amount of hydrogen-containing gas exceeds the design amount, the fuel utilization rate decreases, the amount of hydrogen that does not contribute to power generation increases, and power generation efficiency decreases.
[0013]
Further, in the case of an air electrode support type fuel cell, if the oxygen-containing gas supplied to the fuel cell is smaller than the design gas amount, the air utilization rate increases. If the air utilization rate becomes too large, oxygen, another fuel of the fuel cell reaction, is consumed at the gas supply port side of the fuel cell, and oxygen is not supplied to the gas outlet side of the fuel cell, so-called The phenomenon of air withering occurs.
[0014]
When this phenomenon occurs, the air electrode is reduced, causing a volume change, and at the interface between the electrolyte and the air electrode co-sintered in the atmosphere, stress is generated due to the volume change of the air electrode, and the fuel cell Leads to destruction.
[0015]
For the above reasons, it is necessary to supply the same amount of gas to each fuel cell. However, when there is a variation in the cross-sectional area of the gas flow path formed inside the fuel cell, even if the gas is supplied to the fuel cell at the same pressure, the gas flow The amount of gas flowing in the road varies from fuel cell to fuel cell.
[0016]
In particular, when a support is manufactured by extrusion molding or the like with high productivity, there is a problem that the cross-sectional area of the gas flow path of the fuel cell tends to vary widely.
[0017]
Therefore, variations in the gas flow paths of the fuel cells are managed, and only the fuel cells within the management range are used. However, it takes time and cost to inspect the variation of the gas flow path of the fuel cell, and there is a problem in productivity. In addition, there is a problem that the cost increases due to a decrease in the non-defective rate.
[0018]
In order to solve this problem, for example, a method of measuring the amount of gas supplied to each fuel cell unit and controlling the amount of gas using a valve or the like can be considered, but the structure becomes complicated, Since a control system is required, there are problems such as an increase in the size of the device and an increase in cost.
[0019]
An object of the present invention is to provide a fuel cell and a fuel cell that can supply gas to a plurality of cell bodies uniformly with a simple structure.
[0020]
[Means for Solving the Problems]
The fuel cell of the present invention has a gas flow path with one side serving as a supply port and the other side serving as a discharge port, which is formed in the axial direction, and a power generation unit in which a solid electrolyte is sandwiched between a fuel electrode and an air electrode. And a lid-like member provided at a discharge port side end of the cell body and having a gas discharge suppression hole for suppressing a gas flow rate of the gas flow path. And
[0021]
In such a fuel cell, even if the cross-sectional area of the gas flow path formed in the cell body varies, the fuel cell is provided inside the cell body at the gas outlet side end of the cell body. By providing a lid-like member having a gas discharge suppressing hole for suppressing the gas flow rate in the gas flow path and increasing the fluid resistance, the amount of gas supplied to the fuel cell can be reduced by cutting the gas flow path in the cell body. It is controlled by a lid-like member having a gas emission suppression hole regardless of the area.
[0022]
As a result, the amount of gas supplied to each of the plurality of fuel cells can be easily made uniform, and variations in the amount of power generated by each fuel cell can be easily suppressed. It is possible to prevent the efficiency from being lowered and the fuel cells from being destroyed.
[0023]
In addition, since the amount of gas discharged from the fuel cell is suppressed by the lid member having the gas discharge suppressing hole, the pressure in the gas passage increases, and the porous fuel electrode or It is expected that the amount of gas supplied to the air electrode will increase and the amount of power generation will increase.
[0024]
Further, the fuel cell unit of the present invention is characterized in that the gas discharge suppressing holes provided in the lid-like member have a slit shape.
[0025]
The shape of the gas emission suppression hole may be, for example, a circular hole or a star-like hole, but a slit-shaped hole is the most productive and has good reproducibility. Holes having the same shape can be formed, and the uniformity of the gas amount supplied to each fuel cell can be further improved.
[0026]
Further, in the fuel cell according to the present invention, the cell main body has a plurality of gas flow paths, and a shielding plate of a lid-like member having a gas discharge suppressing hole formed on an end face on the outlet side of the cell main body includes the cell main body. A common gas chamber is provided between the shielding plate and the end face on the outlet side of the cell body.
[0027]
When a plurality of gas flow paths are formed inside one cell main body, the lid-shaped member may be provided with a gas discharge suppression hole communicating with each gas flow path.
[0028]
However, the shape tends to be complicated, and the strength of the member tends to be low. Therefore, the plurality of gas flow paths are spaced apart from each other by a predetermined distance between the gas discharge port side end surface of the cell body having the plurality of gas flow paths and the shielding plate in which the gas discharge suppression holes of the lid member are formed. By providing a common gas chamber communicating with the gas discharge suppressing hole and the gas discharge suppressing hole, a plurality of gas flow paths provided inside the cell body can be communicated, and the gas discharge suppression corresponding to each gas flow path is provided on the lid member. There is no need to provide a plurality of holes, so that the structure of the lid-like member can be simplified, and mounting is easy.
[0029]
Further, a fuel cell of the present invention is characterized in that a plurality of the above-described fuel cells are housed in a housing container.
[0030]
In such a fuel cell, the amount of gas supplied to each fuel cell becomes uniform, and the power generation capacity is improved. Further, it is possible to suppress destruction of fuel cells and deterioration of performance due to insufficient or excessive gas supply. In particular, when the fuel cells are electrically connected in series, the performance degradation of one fuel cell greatly affects the power generation capacity of the entire fuel cell, so that an increase in the electric resistance of the fuel cell is prevented. The fuel cell of the present invention that can be used can prevent significant performance deterioration, particularly in a fuel cell in which fuel cells are connected in series. Further, a simple structure can be achieved without requiring a special control device, and an improvement in power generation efficiency, downsizing of the fuel cell, and cost reduction can be achieved.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show a perspective view and a longitudinal sectional view of one embodiment of the fuel cell unit of the present invention. Note that the same members as those in the conventional technique are denoted by the same reference numerals.
[0032]
In the fuel cell of the present invention, a porous fuel electrode 5, a dense solid electrolyte 7, and a porous solid electrolyte 7 are formed on the surface of a flat columnar support 3 in which a plurality of gas flow paths 1 are formed in the axial direction. The air electrode 9 is sequentially formed to form the cell body A. At the end of the outlet side of the cell body A, a lid-like member 13 having a gas emission suppressing hole 11 is provided. The lid member 13 has a cap shape, and is composed of a shielding plate 13a in which the gas discharge suppression holes 11 are formed, and an annular body 13b fitted to the cell main body A. It has a function of suppressing the gas flow rate flowing through the gas flow path 1 formed inside the main body A.
[0033]
Further, a common gas chamber 15 is formed between the discharge port side end face 14 of the cell body A and the shielding plate 13a. By providing the common gas chamber 15 between the discharge port side end face 14 of the cell body A and the shielding plate 13a in this manner, the gases passing through the plurality of gas flow paths 1 once merge in the common gas chamber 15, For example, only one discharge suppression hole 11 may be provided. The smaller the number of gas emission suppression holes 11, the higher the productivity of the lid-like member 13 and the higher the strength as a member. Further, by providing the common gas chamber 15, the number of contact points between the cell body A and the lid member 13 is reduced, so that the attachment between the cell body A and the lid member 13 is facilitated.
[0034]
In such a fuel cell, the gas supplied to the inside of the cell body A is introduced into the gas flow path 1 from the end opposite to the end on the outlet side of the cell body A, and passes through the common gas chamber 15. The gas passes through the gas discharge suppressing holes 11 provided in the lid 13 and is discharged outside the fuel cell. Further, other gas is supplied to the outside of the fuel cell, and the fuel electrode 5 and the air are mixed in a power generation unit in which a porous fuel electrode 5, a dense solid electrolyte 7, and a porous air electrode 9 are laminated. Power generation based on the oxygen concentration difference between the poles 9 is performed.
[0035]
In this fuel cell, a dense solid electrolyte 7 is formed up to the end of the cell body A in order to prevent gas from entering inside and outside the fuel cell.
[0036]
In such a fuel cell, the support 3 is generally manufactured by using an extrusion molding method with high productivity. However, this molding method has low dimensional accuracy and the shape of the gas flow path 1 inside the fuel cell is low. Tends to vary greatly depending on the fuel cell.
[0037]
As described above, when a stack is manufactured using a plurality of fuel cells in which the shape of the gas flow path 1 varies, and when the stack is fixed to the manifold and the gas flows through the inside of the fuel cell, the gas flows through each fuel cell. There has been a problem that it does not flow evenly between cells. For example, even if a design gas amount corresponding to the number of fuel cells forming the stack is supplied to the stack, a large amount of gas flows through the fuel cell having the large gas flow path 1 but a small amount of the fuel cell has a small gas flow path 1. A phenomenon occurs in which only a small amount of gas flows.
[0038]
This phenomenon is caused by the fact that the pressure loss of the gas flowing through the narrow gas flow path 1 becomes larger than the pressure loss of the gas flowing through the wide gas flow path 1. The flow velocity of the gas flowing through the flow path 1 becomes slow.
[0039]
Since the amount of gas passing through the gas passage 1 is the product of the gas flow velocity and the cross-sectional area of the gas passage 1, the amount of gas flowing through the narrow gas passage 1 is smaller than the amount of gas flowing through the wide gas passage 1. Less. This tendency becomes more conspicuous as the length of the gas flow path 1 in the flow direction is longer.
[0040]
Such a variation in the gas flow rate due to the variation in the shape of the gas flow path 1 may be caused, for example, by connecting a plurality of fuel cells to one gas tank and supplying the gas from one gas tank to the gas flow path 1 of the plurality of fuel cells. In the case of supply, it becomes particularly noticeable, and if there is even one fuel cell in which gas does not easily flow, gas hardly flows in this fuel cell, and excess gas is supplied only to the other fuel cells. As a result, there is a problem that the power generation amount and the power generation efficiency of the entire fuel cell decrease.
[0041]
The fuel cell of the present invention is supplied by providing the lid-like member 13 having the gas discharge suppressing hole 11 at the outlet side end of the cell body A even if the gas flow path 1 has a different sectional area. Since the gas amount can be controlled, the variation in the gas amount supplied between the plurality of fuel cells can be suppressed, and the power generation efficiency decreases due to the decrease in the fuel utilization rate due to the excessive gas flow rate. Further, it is possible to prevent the fuel cell from being destroyed due to the fuel dying caused by the gas flow rate being too small, the performance deterioration of the fuel cell due to the increase in the electric resistance, and the fuel cell from being damaged due to the air dying. In addition, since gas can be uniformly distributed and supplied to each fuel cell, improvement in power generation capacity of the fuel cell and prevention of destruction of the fuel cell can be achieved at the same time. In particular, the effect is remarkable in a series connection type fuel cell in which the characteristic deterioration of one fuel cell greatly affects the characteristics of the whole fuel cell.
[0042]
Further, the pressure of the hydrogen gas or the oxygen-containing gas in the gas flow path 1 can be increased by providing the lid-like member 13 having the gas discharge suppression hole 11 at the end of the cell body A on the outlet side. It is expected that the amount of gas supplied to the porous fuel electrode 5 or the air electrode 9 on the gas flow path 1 side can be increased, and the power generation amount of the fuel cell can be increased.
[0043]
FIG. 3 shows a longitudinal sectional view of another embodiment of the fuel cell unit according to the present invention. In this fuel cell, a plurality of gas flow paths 1 are formed inside the cell body A, and a plurality of gas discharge suppression holes 11 corresponding to the gas flow paths 1 are formed at the outlet end of the cell body A. A lid member 13 is provided. A common gas chamber 15 is provided between the shielding plate 13a provided with the gas discharge suppressing holes 11 and the discharge port side end surface 14 of the cell body.
[0044]
Even in such a fuel cell, the amount of gas supplied between the plurality of fuel cells can be made uniform by providing the gas discharge suppressing holes 11 corresponding to the plurality of gas channels 1 in the lid-like member 13. And the amount of gas supplied to the plurality of gas passages 1 formed inside the cell body A becomes uniform, and the amount of power generation as a fuel cell is improved.
[0045]
FIG. 4 shows a longitudinal sectional view of another embodiment of the fuel cell unit according to the present invention. In this fuel cell, a plurality of gas passages 1 are formed inside the cell body A, and the gas passages 1 of the cell body A correspond to the outlet side end of the cell body A, respectively. A lid-like member 13 provided with a gas emission suppression hole 11 is provided. Even in such a fuel cell, since the gas discharge suppression holes 11 are provided independently in the gas flow paths 1 of the cell body A, the gas amount supplied to each gas flow path 1 can be made uniform. it can.
[0046]
FIG. 5 shows various forms of the lid 13. The gas emission suppressing holes 11 which are through holes provided in the lid member 13 may be circular holes as shown in FIGS. 5 (a) and 5 (b), and FIGS. 5 (c) and 5 (d). , (E).
[0047]
Further, the number of the gas emission suppressing holes 11 is one as shown in FIGS. 5B, 5C and 5D, but is plural as shown in FIGS. 5A and 5E. Is also good. For example, by reducing the number of the gas discharge suppression holes 11 provided in the cover member 13 to one, the structure of the cover member 13 is simplified, and the number of the gas discharge suppression holes 11 is reduced. The production of the member 13 is facilitated, and the strength of the lid 13 is also improved.
[0048]
The lid 13 is preferably made of a heat-resistant metal or the like whose coefficient of thermal expansion is close to that of the cell body A because of its high thermal conductivity. Further, ceramic members such as alumina, zirconia, stabilized zirconia, and partially stabilized zirconia, which are excellent in heat resistance, thermal shock resistance, and strength, and excellent in stability in an oxidizing atmosphere and a reducing atmosphere, are also preferably used.
[0049]
In particular, in the case where excess gas is burned in the vicinity of the gas discharge port side end of the fuel cell, the cell body A is rapidly heated by making the lid member 13 a ceramic having a lower thermal conductivity than metal. Can be protected from destruction.
[0050]
Further, from the viewpoint of the effect of suppressing the amount of gas flow, the shape of the gas discharge suppressing hole 11 provided in the lid 13 is preferably such that the depth of the hole, that is, the thickness of the shielding plate 13a is 2 mm or more, Furthermore, it is desirable that it is 4 mm or more. Further, the width of the gas emission suppression hole 11 in the minor axis direction is preferably 1 mm or less, and more preferably 0.7 mm or less.
[0051]
FIG. 6 shows a longitudinal sectional view (a) of another embodiment of the fuel cell unit according to the present invention, and a perspective view (b) of one embodiment of the lid 13. In this fuel cell, a gas flow path 1 is formed inside a cylindrical column-shaped cell main body A, and a lid-like member 13 having a gas discharge suppressing hole 11 formed at an end of the cell main body A on the outlet side is provided. . For example, even in the case of such a cylindrical column-shaped cell main body A, by providing a lid-like member 13 in which a gas discharge suppression hole 11 is formed at the end of the cell main body A on the outlet side, a plurality of fuel cells can be formed. The amount of gas supplied can be made uniform.
[0052]
The fuel cell of the present invention is configured by storing a plurality of the fuel cells of the present invention in a storage container. In such a fuel cell, the gas can be uniformly distributed and supplied within the fuel cell or between the fuel cells, and the variation in the amount of power generation between the fuel cells can be suppressed. The breakage of the cell can be prevented, and the power generation capacity can be increased.
[0053]
Further, it is not necessary to inspect the gas flow path 1 for each fuel cell, and the productivity is improved.
[0054]
Note that the present invention is not limited to the above-described embodiment, and various changes can be made without changing the gist of the present invention. For example, as long as gas is discharged from the end of the cell main body, the same effect can be obtained even with a one-end sealed type or folded type cell main body. Further, the lid-like member 13 only has to have a function of suppressing gas emission. For example, a porous body or a net-like member may be used instead of the shielding plate 13a and the gas emission suppression hole 11.
[0055]
【The invention's effect】
According to the present invention, the amount of gas supplied to each fuel cell becomes uniform, the power generation capability is excellent, and the destruction of the fuel cell due to insufficient gas supply or excessive gas supply can be suppressed. In addition, it is possible to achieve an improvement in power generation efficiency, a reduction in size of the fuel cell, and a reduction in cost with a simple structure without requiring a special control device.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a fuel cell unit of the present invention.
FIG. 2 is a longitudinal sectional view of the fuel cell unit of FIG.
FIG. 3 is a longitudinal sectional view showing another embodiment of the fuel cell unit of the present invention in which gas emission suppression holes are formed so as to correspond to a plurality of gas flow paths.
FIG. 4 is a longitudinal sectional view showing still another embodiment of the fuel cell unit of the present invention.
5 (a) to 5 (e) are plan views showing various forms of a lid member used for the flat columnar fuel cell of the present invention.
FIG. 6A is a longitudinal sectional view showing a form of a cylindrical fuel cell of the present invention, and FIG. 6B is a perspective view showing a lid member.
FIG. 7 is a longitudinal sectional view showing a conventional fuel cell unit.
[Explanation of symbols]
A: Cell body 1: Gas flow path 3: Support member 5: Fuel electrode 7: Solid electrolyte 9: Air electrode 11: Gas emission suppression hole 13: Lid -Shaped member 13a-shielding plate 13b-annular body 14-end face 15 on the outlet side-common gas chamber

Claims (4)

A gas flow path having one side serving as a supply port and the other side serving as a discharge port is formed in the axial direction, and a column-shaped cell body having a power generation unit in which a solid electrolyte is sandwiched between a fuel electrode and an air electrode; A fuel cell comprising: a lid-like member provided at an end of an exhaust port side of a cell body and formed with a gas discharge suppression hole for suppressing a gas flow rate in the gas flow path. 2. The fuel cell according to claim 1, wherein the gas discharge suppressing hole provided in the lid member has a slit shape. The cell body has a plurality of gas flow paths, and a shielding plate of a lid-like member having a gas discharge suppression hole formed on an end face on the outlet side of the cell body at a predetermined distance from the end face on the outlet side of the cell body. The fuel cell according to claim 1, wherein a common gas chamber is provided between the shielding plate and an end face on the outlet side of the cell body. A fuel cell comprising a plurality of fuel cells according to any one of claims 1 to 3 stored in a storage container.

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